In the fiber optics communication industry, many companies have developed means by which optical fibers can be connected to one another. Splicers, in particular, come in two primary forms: fusion splicers and mechanical splicers. A fusion splicer physically fuses the ends of two optical fibers together by the application of heat, typically from an electrical arc. Fusion splicers are advantageous in that they create splices in which the insertion and return losses are precisely controlled. However, fusion splicing is complicated, expensive, and requires advanced technical equipment not readily suited for use in the field, particularly if local electric power required is not available.
A mechanical splicer is a junction of two fibers aligned with each other and held in place within a ferrule or similar assembly, such as a traditional v-groove alignment ferrule. The fibers are not physically joined as in a fusion splice. Rather, the fiber ends are held very close together within the ferrule aligned with each other, optionally with an optical index matching gel in between, so that light can pass from one end to the other end in a desired path and with the least amount of disturbance. Because of its ease in application and simplicity in terms of labor, training and equipment cost, mechanical splicing is preferred for use in the field, especially when electrical power is hard to reach, and the terminations and splicing points are scattered around, not centralized, such as for installation in multi-dwelling-units.
In the past, the prior art has used v-groove alignment for most of the mechanical connectors as well as for mechanical splice-on connectors. In these configurations, the fibers to be connected are laid in the v-groove such that the fiber tip of one fiber abuts the tip of the second fiber. The fibers are aligned in the v-groove, and they are then locked in the groove by a hard pad or cover (the hardness is usually softer than the glass material itself) pressing into the v-groove. The hard pad and the v-groove form a triangle for securing the fibers.
However, this v-groove alignment may not be the best in the case of connecting two fibers. The v-groove is the same along its length with respect to the mechanical joint. One or both fibers to be mechanically connected will typically have a slightly varying diameter due to manufacturing variations. For example, a fiber out-diameter of a stripped end of a fiber is typically specified to have a diameter of 125 μm, but in reality there is always some variation or eccentricity around the circumference of the fiber. If two fibers are inserted from opposite ends of a v-groove, the variation in diameter will create an offset for the core (the center axis of about 0.8-0.9 μm in diameter) of the fibers. To be more specific, the axis of one fiber may be shifted with respect to the axis of the other fiber. The offset is part of the eccentricity. The eccentricity remains even after the fibers are locked in the v-groove. This tiny eccentricity, which may be only a few microns, will impact the insertion loss as well as the return loss of the junction between the two fibers. In addition, v-groove configured joints often do not apply an evenly-distributed force on the portions of the fibers contained within the groove. This can lead to misalignment of the fiber ends within the joint and can cause additional insertion and return losses.
It is, therefore, desirable to provide a configuration in joints of optical fiber ends that minimizes such an unperfected physical alignment and unwanted insertion and return losses.